|The turbot, its fishery and biology in the Scottish area|
Rae, B.B.; Devlin, S.D.E. (1972). The turbot, its fishery and biology in the Scottish area. Marine Research 1972(1): 1-27
In: Marine Research. Department of Agriculture and Fisheries for Scotland: Edinburgh. ISSN 0076-4493, more
Age composition; Distribution; Food composition; Growth; Landings; Spawning; Scophthalmus maximus (Linnaeus, 1758) [WoRMS]; Marine
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Following a short account of the distribution of the turbot, the Scottish and English turbot fisheries are reviewed from the earliest published landings of this species. Scottish landings reached their highest level in 1947 and English in 1920. Scottish turbot landings have declined from 25,000 cwt in 1947 to < 2,000 cwt in 1968 and 1969, and English landings have declined from 85,000 cwt in 1947 to similar to 20,000 cwt in 1969. Biological data on turbot collected on Scottish research vessels, mainly in the northern North Sea between the 2 wars and after the 2nd war have revealed that small turbot of up to 30 cm are largely confined to depths of < 11 m while fish of 31-45 cm are taken mainly in waters of 21-50 m. Turbot of 46-85 cm are mainly caught at depths of 51-150 m, while a few are taken in deeper water. Age-analysis of the fish from examination of the otoliths shows a wide range from one to at least 19 years. By combining length measurements with age, the growth of the turbot is shown to be faster than other native spp of flatfish, with the possible exception of the halibut. The sex ratio and spawning of the turbot is also considered on the available evidence and the stomach contents are analysed. The latter suggest seasonal differences in feeding with some resemblance to the feeding characteristics of other flatfish. The decline in the annual landings of turbot in the United Kingdom is considered in the light of the biological evidence. This suggests that the decline in the numbers of turbot in the northern North Sea may be owing to fewer adult and adolescent turbot migrating northwards from the southern North sea where the principal nursery grounds for this sp are located. The numbers of young turbot emanating from local Scottish nurseries by themselves are regarded as inadequate for the maintenance of the adult stocks in the northern North Sea. Although ther5e has been a general fall in European turbot landings in recent yrs, Dutch landings have increased, probably as a result of greater fishing effort and improvements in the efficiency of the flatfish trawls employed.